1. Field of the Invention
The present invention relates to a medical image observation system that displays medical image data acquired by a medical image acquisition apparatus. In particular, the present invention relates to a medical image observation system that generates medical image data associated with medical image data that was generated in a previous examination.
2. Description of the Related Art
Medical image data acquired by a medical image acquisition apparatus such as an X-ray CT (X-ray Computed Tomography) apparatus and an MRI (Magnetic Resonance Imaging) apparatus is managed in a picture archiving and communication system (PACS) connected via a network. This picture archiving and communication system (PACS) is connected via a network to a hospital information system (HIS) and a radiology information system (RIS). An operator such as a physician can interpret a medical image by reading desired medical image data from a picture archiving and communication system using a client terminal on the network (Japanese Published Unexamined Application No. 1993-81156).
Furthermore, a plurality of sets of medical image data acquired by the medical image acquisition apparatus are classified for each patient according to the DICOM (Digital Imaging and Communication in Medicine) specification, and the classification by patient is further classified per examination. The examination consists of a series of medical image data. The series includes a plurality of sets of medical image data. The classification of a plurality of sets of medical image data with such a structure shows that, with the patient assumed to be at the top level, a specific examination is performed on the patient, the examination consists of a series of medical image data, and the series includes a plurality of sets of medical image data.
In a client terminal, a medical image acquired in an examination newly performed on a patient (hereinafter may be referred to as “new examination”) and a medical image acquired in an examination performed in the past (hereinafter may be referred to as “previous examination”) for a patient may be compared and interpreted. In this case, the client terminal inclusively reads all medical image data included in the series of the new examination from the picture archiving and communication system, and generates a medical image to be compared with the medical image of the previous examination based on all of the medical image data.
For example, when MPR (Multi Planar Reconstruction) processing is performed on medical image data acquired in a previous examination, image data (MPR image data) on an arbitrary cross-section generated through MPR process is stored in the medical image storage system. Additionally, if the MPR image generated in the previous examination is compared and interpreted with an MPR image of a new examination, it is necessary to generate MPR image data based on a plurality of sets of medical image data acquired in the new examination. For example, by generating MPR image data of the new examination that has the same segment of the cross-section as the MPR image of the previous examination, the MPR image of the previous examination and the MPR image of the new examination are compared and interpreted.
To generate MPR image data of a new examination on the client terminal, all medical image data acquired in the new examination is conventionally imported into the client terminal from the picture archiving and communication system. MPR image data to be compared is then generated on the client terminal based on a plurality of sets of read medical image data.
As stated above, when a medical image of a new examination and a medical image of a previous examination are compared and interpreted on the client terminal, all medical image data of the new examination is conventionally imported into the client terminal from the picture archiving and communication system. For example, when an MPR image of a previous examination and an MPR image of a new examination are compared and interpreted, all medical image data included in the new examination is imported into the client terminal from the picture archiving and communication system in order to generate an MPR image of the new examination on the client terminal.
However, with the method of the related art, the volume of medical image data that is sent to the client terminal from the picture archiving and communication system is so large that it is necessary to install large-capacity memory on the client terminal. In particular, when medical image data is imported into a general-use personal computer for comparison and interpretation, the volume of medical image data to be read is also limited, because the capacity of the memory is limited. Therefore, it is possible that the medical image data that is necessary for interpretation will not be sufficiently read.
Moreover, because the volume of medical image data that is sent to the client terminal from the picture archiving and communication system is large, the amount of time required for importing it into the client terminal increases. Thereby, the time necessary for interpretation increases, resulting in a difficulty to make a diagnosis efficiently.
Moreover, there is a desire to import medical image data included in a plurality of series from the picture archiving and communication system into the client terminal in order to compare and view it. In such a case, all medical image data included in each series is conventionally imported into the client terminal from the picture archiving and communication system. Therefore, a problem arises in which large-capacity memory is needed on the client terminal, resulting in an increase in time for reading. Therefore, it is difficult to make a diagnosis efficiently in this case as well.